| --- |
| license: other |
| license_name: cc-by-nc-4.0-and-apache-2.0 |
| license_link: https://huggingface.co/afrispeech/Akiti-TTS |
| language: |
| - tw |
| library_name: phoonnx |
| pipeline_tag: text-to-speech |
| tags: |
| - onnx |
| - tts |
| - twi |
| - akan |
| - neutts |
| - neucodec |
| base_model: |
| - afrispeech/Akiti-TTS |
| - neuphonic/neucodec-onnx-decoder-int8 |
| --- |
| |
| # phoonnx-neutts — Akiti-TTS (Asante Twi), ONNX |
|
|
| ONNX conversion of [afrispeech/Akiti-TTS](https://huggingface.co/afrispeech/Akiti-TTS), |
| an Asante Twi text-to-speech model, packaged for |
| [phoonnx](https://github.com/TigreGotico/phoonnx). This repository holds converted |
| weights only — no new training was done. |
|
|
| Akiti-TTS is a LoRA fine-tune of |
| [pnnbao-ump/VieNeu-TTS-0.3B](https://huggingface.co/pnnbao-ump/VieNeu-TTS-0.3B), which |
| comes from Neuphonic's NeuTTS Air family: a Qwen3 causal LM that emits |
| [NeuCodec](https://huggingface.co/neuphonic/neucodec) audio tokens. |
|
|
| ## Files (`akiti-twi-onnx/`) |
|
|
| | File | What it is | |
| |---|---| |
| | `neutts_lm.onnx` + `neutts_lm.onnx.data` | Qwen3 backbone, fp32, KV-cached. **The graph needs its `.data` sidecar next to it.** | |
| | `neutts_lm_int8.onnx` | The same graph, dynamically quantized to int8. Smaller, but measurably lower quality — it puts the end-of-speech token in the top 5 at the first step, where fp32 does not. | |
| | `neucodec_decoder.onnx` | Copy of [neuphonic/neucodec-onnx-decoder-int8](https://huggingface.co/neuphonic/neucodec-onnx-decoder-int8) (Apache-2.0), unmodified. | |
| | `tokenizer.json` | The checkpoint's own BPE, copied from upstream. | |
| | `voices.json` | The nine voice presets, copied from [AfriSpeech/akiti-tts](https://github.com/AfriSpeech/akiti-tts) (MIT). | |
| | `neutts_onnx_meta.json` | Architecture summary written by the export script. | |
|
|
| ## Graph contract |
|
|
| `neutts_lm.onnx` serves prefill and decode: the same graph with a different past length. |
|
|
| ``` |
| inputs input_ids int64 [1, S] prompt tokens, or 1 token per step |
| attention_mask int64 [1, P + S] ones over past and current tokens |
| position_ids int64 [1, S] absolute positions, P .. P+S-1 |
| past_key_<i> fp32 [1, 4, P, 64] i in 0..27 |
| past_value_<i> fp32 [1, 4, P, 64] |
| outputs logits fp32 [1, 66938] last position only |
| present_key_<i> / present_value_<i> fp32 [1, 4, P + S, 64] |
| ``` |
|
|
| `neucodec_decoder.onnx` takes `codes` int32 `[1, 1, N]` and returns `audio` float32 |
| `[1, 1, 480 * (N - 1)]` at 24 kHz — 50 codec tokens per second of audio. |
|
|
| ## Prompt format |
|
|
| The LM is prompted with phonemes, not letters. Text is phonemized by espeak-ng using the |
| **`lfn`** (Lingua Franca Nova) voice, which is what the checkpoint was trained with; |
| espeak-ng has no Twi voice, and `lfn`'s five-vowel orthography reads Twi spelling closely. |
|
|
| ``` |
| <|TEXT_PROMPT_START|>{reference phones} {target phones}<|TEXT_PROMPT_END|> |
| <|SPEECH_GENERATION_START|>{<|speech_c|> for c in reference codes} |
| ``` |
|
|
| Generation continues that speech-token run until `<|SPEECH_GENERATION_END|>` or EOS. |
|
|
| ## Fidelity |
|
|
| Exported with `scripts/conversion/neutts/export_neutts_onnx.py` in phoonnx. Against the |
| torch model on a fixed prompt, max absolute logit difference: |
|
|
| | | fp32 ONNX | |
| |---|---| |
| | prefill | 4.10e-05 | |
| | decode (8 steps) | 2.96e-05 | |
|
|
| The fp32 graph's top-5 next tokens on a real prompt are identical to torch's, in the same |
| order and to two decimal places. |
|
|
| ## Licensing |
|
|
| The pieces carry different licenses, and one of them is inconsistent upstream. Read this |
| before using the model. |
|
|
| - **`afrispeech/Akiti-TTS` weights** — the Hugging Face model card declares |
| **CC BY-NC 4.0** (non-commercial). The |
| [GitHub README](https://github.com/AfriSpeech/akiti-tts) instead states the weights are |
| Apache-2.0. These two statements disagree. This mirror records both and resolves |
| neither; treat the stricter of the two (**non-commercial**) as binding until AfriSpeech |
| clarifies. The GitHub repository's *code* is MIT, which is not in dispute. |
| - **`neucodec_decoder.onnx`** — Apache-2.0, from Neuphonic. |
| - **`voices.json`** — from the MIT-licensed AfriSpeech/akiti-tts repository. |
| |
| Attribution: AfriSpeech / Ghana NLP (Akiti-TTS), pnnbao-ump (VieNeu-TTS-0.3B), Neuphonic |
| (NeuTTS Air, NeuCodec). |
| |
